The present invention relates to a semiconductor device, a semiconductor system including the same, and a control method of a semiconductor device. For example, the present invention relates to a semiconductor device, a semiconductor system including the same, and a control method of a semiconductor device suitable for performing communication according to a correct communication standard.
For data communication between a controller and a module, an I2C (Inter-Integrated Circuit) mode has been widely used as the communication mode. In the I2C communication, since the controller can be connected with a plurality of modules through a common bus, the number of signal lines can be reduced.
Examples of the modules include a sensor, a liquid crystal display, and so on. It should be noted that some of the modules have a drive voltage (operating voltage) different from that of the other modules. Therefore, the controller needs to supply a drive voltage that is specified by a communication standard and supported by a module with which the controller communicates, and perform communication at the drive voltage (signal amplitude) supported by the module.
To satisfy this requirement, there is a method in which the drive voltage of a module is checked in advance, for example, and the drive voltage supplied from the controller to the module is manually set.
However, the present inventors have found the following problem. There is a possibility of an erroneous setting in the above-described method in which the drive voltage is manually set. When an erroneous setting occurs, normal data communication cannot be performed any longer. Further, if a drive voltage higher than the rated voltage is applied to a module, the module could be broken.
Japanese Unexamined Patent Application Publication No. 2010-154615 discloses a countermeasure for this problem. In a power supply voltage supply system disclosed in Japanese Unexamined Patent Application Publication No. 2010-154615, a device (module) includes a pattern circuit that changes connections among a plurality of resistive elements according to power supply information held in a power receiving unit of the device, and a power supply voltage supply unit (control device) controls a power supply voltage supplied to the device based on a combined resistance of the plurality of resistive elements read from the device through a control signal line. As a result, a correct power supply voltage is supplied to the device.